The Toegye's Vital-seeing reading method is divided into three mainstreams. They are a grasp of words' meaning by considering reason, a grasp of main cause by examining the relationship of the thing and its functions, a grasp of the sages' writing by discriminating Wonducheo and Pumsujicho. The three mainstreams can be made into one concept, that is, 'to see vitally the writing based on the main cause and to grasp the essentials'. This can not be discussed without an innate norm, 'Sungjeukri', and a principle of existence, 'Simwitaegeuk'. As 'Ri' of 'Sungjeukri' is active, the Vital-seeing reading method can be a method of Hwalrichein. And because the Vital-seeing reading method explains a person focused on Simbal and Simwitaegeuk, it is possible to say that it is a method based on self-regulating volition. The Vital-seeing reading method has two functions. One is that it changes a language of dead object into a language of living object. The other is that it makes a reader proceed from Yumdonggujung to Tonggwandongjung. With the two functions, the Vital-seeing reading theory changes the writing of the sages into a living thing, and helps a reader to have a orientation which reach Chuninhapil.